10 papers
Zeeman-Doppler imaging of five young solar-type stars
T. Willamo, J. J. Lehtinen, T. Hackman +5
The magnetic activity of the Sun changes with the solar cycle. Similar cycles are found in other stars as well, but their details are not known to a similar degree. Characterising…
Compressible test-field method and its application to shear dynamos
Maarit J. Käpylä, Matthias Rheinhardt, Axel Brandenburg
In this study we present a compressible test-field method (CTFM) for computing effect and turbulent magnetic diffusivity tensors, as well as those relevant for mean ponderomoti…
Modeling the interplay between epidemics and regional socio-economics
Jan E. Snellman, Rafael A. Barrio, Kimmo K. Kaski +1
In this study we present a dynamical agent-based model to investigate the interplay between the socio-economy of and SEIRS-type epidemic spreading over a geographical area, divided…
Scalable communication for high-order stencil computations using CUDA-aware MPI
Johannes Pekkilä, Miikka S. Väisälä, Maarit J. Käpylä +2
Modern compute nodes in high-performance computing provide a tremendous level of parallelism and processing power. However, as arithmetic performance has been observed to increase…
Generation of mean flows in rotating anisotropic turbulence: The case of solar near-surface shear layer
A. Barekat, M. J. Käpylä, P. J. Käpylä +2
The radial gradient of the rotation rate in the near-surface shear layer (NSSL) of the Sun is independent of latitude and radius. Theoretical mean-field models have been successful…
A Knee-Point in the Rotation-Activity Scaling of Late-type Stars with a Connection to Dynamo Transitions
Jyri J. Lehtinen, Maarit J. Käpylä, Nigul Olspert +1
The magnetic activity of late-type stars is correlated with their rotation rates. Up to a certain limit, stars with smaller Rossby numbers, defined as the rotation period divided b…